using ControlPlane.Core.Models;
using Npgsql;

namespace ControlPlane.Api.Services;

public class OpcService(NpgsqlDataSource db)
{
    // ── Helpers ──────────────────────────────────────────────────────────────

    private static OpcRecord ReadOpc(NpgsqlDataReader r) => new(
        r.GetGuid(0),
        r.GetString(1),
        r.GetString(2),
        r.GetString(3),
        r.GetString(4),
        r.GetString(5),
        r.GetString(6),
        r.GetString(7),
        r.GetDateTime(8),
        r.GetDateTime(9)
    );

    private static OpcNote ReadNote(NpgsqlDataReader r) => new(
        r.GetGuid(0),
        r.GetGuid(1),
        r.GetString(2),
        r.GetString(3),
        r.GetDateTime(4)
    );

    private static OpcArtifact ReadArtifact(NpgsqlDataReader r) => new(
        r.GetGuid(0),
        r.GetGuid(1),
        r.GetString(2),
        r.GetString(3),
        r.GetString(4),
        r.GetDateTime(5),
        r.GetDateTime(6)
    );

    // ── Next OPC number ───────────────────────────────────────────────────────

    public async Task<string> NextNumberAsync(CancellationToken ct = default)
    {
        await using var cmd = db.CreateCommand(
            "SELECT number FROM opc ORDER BY CAST(TRIM(SUBSTRING(number FROM 7)) AS INTEGER) DESC LIMIT 1");
        var last = await cmd.ExecuteScalarAsync(ct) as string;
        if (last is null) return "OPC # 0001";
        if (int.TryParse(last[6..], out var n))
            return $"OPC # {n + 1:D4}";
        return "OPC # 0001";
    }

    // ── OPC CRUD ──────────────────────────────────────────────────────────────

    public async Task<List<OpcRecord>> ListAsync(
        string? typeFilter = null, string? statusFilter = null,
        CancellationToken ct = default)
    {
        var sql = """
            SELECT id, number, title, description, type, status, priority, assignee,
                   created_at, updated_at
            FROM   opc
            WHERE  ($1::text IS NULL OR type   = $1)
              AND  ($2::text IS NULL OR status = $2)
            ORDER BY created_at DESC
            """;
        await using var cmd = db.CreateCommand(sql);
        cmd.Parameters.AddWithValue(typeFilter   ?? (object)DBNull.Value);
        cmd.Parameters.AddWithValue(statusFilter ?? (object)DBNull.Value);
        await using var r = await cmd.ExecuteReaderAsync(ct);
        var list = new List<OpcRecord>();
        while (await r.ReadAsync(ct)) list.Add(ReadOpc(r));
        return list;
    }

    public async Task<OpcRecord?> GetAsync(Guid id, CancellationToken ct = default)
    {
        await using var cmd = db.CreateCommand(
            "SELECT id, number, title, description, type, status, priority, assignee, created_at, updated_at FROM opc WHERE id = $1");
        cmd.Parameters.AddWithValue(id);
        await using var r = await cmd.ExecuteReaderAsync(ct);
        return await r.ReadAsync(ct) ? ReadOpc(r) : null;
    }

    public async Task<OpcRecord> CreateAsync(CreateOpcRequest req, CancellationToken ct = default)
    {
        var number = await NextNumberAsync(ct);
        var sql = """
            INSERT INTO opc (number, title, description, type, status, priority, assignee)
            VALUES ($1, $2, $3, $4, 'New', $5, $6)
            RETURNING id, number, title, description, type, status, priority, assignee,
                      created_at, updated_at
            """;
        await using var cmd = db.CreateCommand(sql);
        cmd.Parameters.AddWithValue(number);
        cmd.Parameters.AddWithValue(req.Title);
        cmd.Parameters.AddWithValue(req.Description);
        cmd.Parameters.AddWithValue(req.Type);
        cmd.Parameters.AddWithValue(req.Priority);
        cmd.Parameters.AddWithValue(req.Assignee);
        await using var r = await cmd.ExecuteReaderAsync(ct);
        await r.ReadAsync(ct);
        return ReadOpc(r);
    }

    public async Task<OpcRecord?> UpdateAsync(Guid id, UpdateOpcRequest req, CancellationToken ct = default)
    {
        var sql = """
            UPDATE opc SET
                title       = COALESCE($2, title),
                description = COALESCE($3, description),
                type        = COALESCE($4, type),
                status      = COALESCE($5, status),
                priority    = COALESCE($6, priority),
                assignee    = COALESCE($7, assignee),
                updated_at  = NOW()
            WHERE id = $1
            RETURNING id, number, title, description, type, status, priority, assignee,
                      created_at, updated_at
            """;
        await using var cmd = db.CreateCommand(sql);
        cmd.Parameters.AddWithValue(id);
        cmd.Parameters.AddWithValue(req.Title    ?? (object)DBNull.Value);
        cmd.Parameters.AddWithValue(req.Description ?? (object)DBNull.Value);
        cmd.Parameters.AddWithValue(req.Type     ?? (object)DBNull.Value);
        cmd.Parameters.AddWithValue(req.Status   ?? (object)DBNull.Value);
        cmd.Parameters.AddWithValue(req.Priority ?? (object)DBNull.Value);
        cmd.Parameters.AddWithValue(req.Assignee ?? (object)DBNull.Value);
        await using var r = await cmd.ExecuteReaderAsync(ct);
        return await r.ReadAsync(ct) ? ReadOpc(r) : null;
    }

    public async Task<bool> DeleteAsync(Guid id, CancellationToken ct = default)
    {
        await using var cmd = db.CreateCommand("DELETE FROM opc WHERE id = $1");
        cmd.Parameters.AddWithValue(id);
        return await cmd.ExecuteNonQueryAsync(ct) > 0;
    }

    // ── Notes ──────────────────────────────────────────────────────────────────

    public async Task<List<OpcNote>> ListNotesAsync(Guid opcId, CancellationToken ct = default)
    {
        await using var cmd = db.CreateCommand(
            "SELECT id, opc_id, author, content, created_at FROM opc_note WHERE opc_id = $1 ORDER BY created_at ASC");
        cmd.Parameters.AddWithValue(opcId);
        await using var r = await cmd.ExecuteReaderAsync(ct);
        var list = new List<OpcNote>();
        while (await r.ReadAsync(ct)) list.Add(ReadNote(r));
        return list;
    }

    public async Task<OpcNote> AddNoteAsync(Guid opcId, AddNoteRequest req, CancellationToken ct = default)
    {
        var sql = """
            INSERT INTO opc_note (opc_id, author, content)
            VALUES ($1, $2, $3)
            RETURNING id, opc_id, author, content, created_at
            """;
        await using var cmd = db.CreateCommand(sql);
        cmd.Parameters.AddWithValue(opcId);
        cmd.Parameters.AddWithValue(req.Author);
        cmd.Parameters.AddWithValue(req.Content);
        await using var r = await cmd.ExecuteReaderAsync(ct);
        await r.ReadAsync(ct);
        return ReadNote(r);
    }

    // ── Artifacts ─────────────────────────────────────────────────────────────

    public async Task<List<OpcArtifact>> ListArtifactsAsync(Guid opcId, string? artifactType = null, CancellationToken ct = default)
    {
        var sql = """
            SELECT id, opc_id, artifact_type, title, content, created_at, updated_at
            FROM   opc_artifact
            WHERE  opc_id = $1
              AND  ($2::text IS NULL OR artifact_type = $2)
            ORDER BY created_at ASC
            """;
        await using var cmd = db.CreateCommand(sql);
        cmd.Parameters.AddWithValue(opcId);
        cmd.Parameters.AddWithValue(artifactType ?? (object)DBNull.Value);
        await using var r = await cmd.ExecuteReaderAsync(ct);
        var list = new List<OpcArtifact>();
        while (await r.ReadAsync(ct)) list.Add(ReadArtifact(r));
        return list;
    }

    public async Task<OpcArtifact> UpsertArtifactAsync(Guid opcId, UpsertArtifactRequest req, CancellationToken ct = default)
    {
        var sql = """
            INSERT INTO opc_artifact (opc_id, artifact_type, title, content)
            VALUES ($1, $2, $3, $4)
            ON CONFLICT DO NOTHING
            RETURNING id, opc_id, artifact_type, title, content, created_at, updated_at
            """;
        // Simple insert; for updates use artifact id endpoint
        await using var cmd = db.CreateCommand(sql);
        cmd.Parameters.AddWithValue(opcId);
        cmd.Parameters.AddWithValue(req.ArtifactType);
        cmd.Parameters.AddWithValue(req.Title);
        cmd.Parameters.AddWithValue(req.Content);
        await using var r = await cmd.ExecuteReaderAsync(ct);
        await r.ReadAsync(ct);
        return ReadArtifact(r);
    }

    public async Task<OpcArtifact?> UpdateArtifactAsync(Guid artifactId, UpsertArtifactRequest req, CancellationToken ct = default)
    {
        var sql = """
            UPDATE opc_artifact SET
                title      = $2,
                content    = $3,
                updated_at = NOW()
            WHERE id = $1
            RETURNING id, opc_id, artifact_type, title, content, created_at, updated_at
            """;
        await using var cmd = db.CreateCommand(sql);
        cmd.Parameters.AddWithValue(artifactId);
        cmd.Parameters.AddWithValue(req.Title);
        cmd.Parameters.AddWithValue(req.Content);
        await using var r = await cmd.ExecuteReaderAsync(ct);
        return await r.ReadAsync(ct) ? ReadArtifact(r) : null;
    }

    public async Task<bool> DeleteArtifactAsync(Guid artifactId, CancellationToken ct = default)
    {
        await using var cmd = db.CreateCommand("DELETE FROM opc_artifact WHERE id = $1");
        cmd.Parameters.AddWithValue(artifactId);
        return await cmd.ExecuteNonQueryAsync(ct) > 0;
    }

    // ── Pinned commits ────────────────────────────────────────────────────────

    private static OpcPinnedCommit ReadPinnedCommit(NpgsqlDataReader r) => new(
        r.GetGuid(0),
        r.GetString(1),
        r.GetString(2),
        r.GetString(3),
        r.GetString(4),
        r.GetDateTime(5),
        r.GetString(6)
    );

    public async Task<List<OpcPinnedCommit>> ListPinnedCommitsAsync(Guid opcId, CancellationToken ct = default)
    {
        await using var cmd = db.CreateCommand(
            "SELECT opc_id, hash, short_hash, subject, author, pinned_at, pinned_by FROM opc_pinned_commit WHERE opc_id = $1 ORDER BY pinned_at DESC");
        cmd.Parameters.AddWithValue(opcId);
        await using var r = await cmd.ExecuteReaderAsync(ct);
        var list = new List<OpcPinnedCommit>();
        while (await r.ReadAsync(ct)) list.Add(ReadPinnedCommit(r));
        return list;
    }

    public async Task<OpcPinnedCommit?> PinCommitAsync(
        Guid opcId, string hash, string shortHash, string subject, string author, string pinnedBy,
        CancellationToken ct = default)
    {
        // Verify the OPC exists
        await using var existsCmd = db.CreateCommand("SELECT 1 FROM opc WHERE id = $1");
        existsCmd.Parameters.AddWithValue(opcId);
        var exists = await existsCmd.ExecuteScalarAsync(ct);
        if (exists is null) return null;

        var sql = """
            INSERT INTO opc_pinned_commit (opc_id, hash, short_hash, subject, author, pinned_by)
            VALUES ($1, $2, $3, $4, $5, $6)
            ON CONFLICT (opc_id, hash) DO UPDATE SET
                short_hash = EXCLUDED.short_hash,
                subject    = EXCLUDED.subject,
                author     = EXCLUDED.author,
                pinned_by  = EXCLUDED.pinned_by,
                pinned_at  = NOW()
            RETURNING opc_id, hash, short_hash, subject, author, pinned_at, pinned_by
            """;
        await using var cmd = db.CreateCommand(sql);
        cmd.Parameters.AddWithValue(opcId);
        cmd.Parameters.AddWithValue(hash);
        cmd.Parameters.AddWithValue(shortHash);
        cmd.Parameters.AddWithValue(subject);
        cmd.Parameters.AddWithValue(author);
        cmd.Parameters.AddWithValue(pinnedBy);
        await using var r = await cmd.ExecuteReaderAsync(ct);
        return await r.ReadAsync(ct) ? ReadPinnedCommit(r) : null;
    }

    public async Task<bool> UnpinCommitAsync(Guid opcId, string hash, CancellationToken ct = default)
    {
        await using var cmd = db.CreateCommand(
            "DELETE FROM opc_pinned_commit WHERE opc_id = $1 AND hash = $2");
        cmd.Parameters.AddWithValue(opcId);
        cmd.Parameters.AddWithValue(hash);
        return await cmd.ExecuteNonQueryAsync(ct) > 0;
    }
}