package api

import (
	"context"
	"net/http"
	"time"

	"github.com/danielgtaylor/huma/v2"
	"github.com/google/uuid"
	"github.com/jackc/pgx/v5/pgtype"

	"completed/internal/db"
	"completed/internal/model"
)

func RegisterRoutes(api huma.API, queries db.Querier) {
	// Root/Hello Route
	huma.Register(api, huma.Operation{
		OperationID: "get-hello",
		Method:      http.MethodGet,
		Path:        "/hello",
		Summary:     "Say Hello",
		Description: "Returns a friendly hello message.",
	}, func(ctx context.Context, input *struct{}) (*struct {
		Body struct {
			Message string `json:"message"`
		}
	}, error) {
		resp := &struct {
			Body struct {
				Message string `json:"message"`
			}
		}{}
		resp.Body.Message = "Hello from Huma + Echo!"
		return resp, nil
	})

	registerAuthRoutes(api, queries)
	registerPlatformRoutes(api, queries)
	registerGameRoutes(api, queries)
}

// --- Platform Routes ---
//
// Platforms are a shared list: every authenticated user reads the same
// rows, unlike games, which are private per user. None of the queries
// below filter by user_id, because platform has no such column. Reading
// the list only requires being logged in (addAuth); adding, renaming or
// deleting a platform requires being an admin (addAdminAuth), since that
// changes what everyone else sees.

func registerPlatformRoutes(api huma.API, queries db.Querier) {
	listOp := huma.Operation{
		OperationID: "list-platforms",
		Method:      http.MethodGet,
		Path:        "/api/platforms",
		Summary:     "List Platforms",
	}
	addAuth(&listOp, api, queries)
	huma.Register(api, listOp, func(ctx context.Context, input *struct{}) (*struct{ Body []model.Platform }, error) {
		platforms, err := queries.ListPlatforms(ctx)
		if err != nil {
			return nil, dbError(err)
		}
		dtos := make([]model.Platform, len(platforms))
		for i, p := range platforms {
			dtos[i] = model.Platform{ID: p.ID.String(), Name: p.Name}
		}
		return &struct{ Body []model.Platform }{Body: dtos}, nil
	})

	getOp := huma.Operation{
		OperationID: "get-platform",
		Method:      http.MethodGet,
		Path:        "/api/platforms/{id}",
		Summary:     "Get Platform",
	}
	addAuth(&getOp, api, queries)
	huma.Register(api, getOp, func(ctx context.Context, input *struct {
		ID uuid.UUID `path:"id"`
	}) (*struct{ Body model.Platform }, error) {
		p, err := queries.GetPlatform(ctx, input.ID)
		if err != nil {
			return nil, dbError(err)
		}
		return &struct{ Body model.Platform }{Body: model.Platform{ID: p.ID.String(), Name: p.Name}}, nil
	})

	createOp := huma.Operation{
		OperationID: "create-platform",
		Method:      http.MethodPost,
		Path:        "/api/platforms",
		Summary:     "Create Platform",
	}
	addAdminAuth(&createOp, api, queries)
	huma.Register(api, createOp, func(ctx context.Context, input *struct{ Body model.PlatformInput }) (*struct{ Body model.Platform }, error) {
		platform, err := queries.CreatePlatform(ctx, input.Body.Name)
		if err != nil {
			return nil, dbError(err)
		}
		return &struct{ Body model.Platform }{Body: model.Platform{ID: platform.ID.String(), Name: platform.Name}}, nil
	})

	updateOp := huma.Operation{
		OperationID: "update-platform",
		Method:      http.MethodPut,
		Path:        "/api/platforms/{id}",
		Summary:     "Update Platform",
	}
	addAdminAuth(&updateOp, api, queries)
	huma.Register(api, updateOp, func(ctx context.Context, input *struct {
		ID   uuid.UUID `path:"id"`
		Body model.PlatformInput
	}) (*struct{ Body model.Platform }, error) {
		platform, err := queries.UpdatePlatform(ctx, db.UpdatePlatformParams{
			ID:   input.ID,
			Name: input.Body.Name,
		})
		if err != nil {
			return nil, dbError(err)
		}
		return &struct{ Body model.Platform }{Body: model.Platform{ID: platform.ID.String(), Name: platform.Name}}, nil
	})

	deleteOp := huma.Operation{
		OperationID: "delete-platform",
		Method:      http.MethodDelete,
		Path:        "/api/platforms/{id}",
		Summary:     "Delete Platform",
	}
	addAdminAuth(&deleteOp, api, queries)
	huma.Register(api, deleteOp, func(ctx context.Context, input *struct {
		ID uuid.UUID `path:"id"`
	}) (*struct{}, error) {
		// Checked separately so a 0-rows result from DeletePlatform below can
		// only mean "blocked by games referencing it", not "doesn't exist" -
		// soft delete means the FK alone can't tell the two apart (see
		// DeletePlatform's comment in db/query.sql). Accepts a race where
		// the platform is deleted between these two queries; harmless, since
		// the second query would then just affect 0 rows and report 409
		// instead of the 404 a plain retry would hit anyway.
		if _, err := queries.GetPlatform(ctx, input.ID); err != nil {
			return nil, dbError(err)
		}

		rows, err := queries.DeletePlatform(ctx, input.ID)
		if err != nil {
			return nil, dbError(err)
		}
		if rows == 0 {
			return nil, huma.Error409Conflict("platform still has games; delete or reassign them first")
		}
		return nil, nil
	})
}

// --- Game Routes ---

// formatDate and parseDate convert between the API's YYYY-MM-DD strings and
// pgtype.Date. CreateGame, GetGame, ListGames and UpdateGame each return a
// distinct sqlc row type with identical fields (id/name/platform_id/
// platform_name/score/release_date/finished), so the DTO conversion itself
// is written out at each call site rather than factored into one function.
func formatDate(d pgtype.Date) string {
	if !d.Valid {
		return ""
	}
	return d.Time.Format("2006-01-02")
}

// parseDate parses a YYYY-MM-DD string into a pgtype.Date. An empty string
// parses to an invalid/NULL date, which is valid for the optional
// "finished" field but rejected separately for the required release_date.
func parseDate(s string) (pgtype.Date, error) {
	if s == "" {
		return pgtype.Date{}, nil
	}
	t, err := time.Parse("2006-01-02", s)
	if err != nil {
		return pgtype.Date{}, err
	}
	return pgtype.Date{Time: t, Valid: true}, nil
}

func registerGameRoutes(api huma.API, queries db.Querier) {
	listOp := huma.Operation{
		OperationID: "list-games",
		Method:      http.MethodGet,
		Path:        "/api/games",
		Summary:     "List Games",
	}
	addAuth(&listOp, api, queries)
	huma.Register(api, listOp, func(ctx context.Context, input *struct{}) (*struct{ Body []model.Game }, error) {
		games, err := queries.ListGames(ctx, userFromContext(ctx).ID)
		if err != nil {
			return nil, dbError(err)
		}
		dtos := make([]model.Game, len(games))
		for i, g := range games {
			dtos[i] = model.Game{
				ID:           g.ID.String(),
				Name:         g.Name,
				PlatformID:   g.PlatformID.String(),
				PlatformName: g.PlatformName,
				Score:        g.Score,
				ReleaseDate:  formatDate(g.ReleaseDate),
				Finished:     formatDate(g.Finished),
			}
		}
		return &struct{ Body []model.Game }{Body: dtos}, nil
	})

	getOp := huma.Operation{
		OperationID: "get-game",
		Method:      http.MethodGet,
		Path:        "/api/games/{id}",
		Summary:     "Get Game",
	}
	addAuth(&getOp, api, queries)
	huma.Register(api, getOp, func(ctx context.Context, input *struct {
		ID uuid.UUID `path:"id"`
	}) (*struct{ Body model.Game }, error) {
		g, err := queries.GetGame(ctx, db.GetGameParams{ID: input.ID, UserID: userFromContext(ctx).ID})
		if err != nil {
			return nil, dbError(err)
		}
		return &struct{ Body model.Game }{Body: model.Game{
			ID:           g.ID.String(),
			Name:         g.Name,
			PlatformID:   g.PlatformID.String(),
			PlatformName: g.PlatformName,
			Score:        g.Score,
			ReleaseDate:  formatDate(g.ReleaseDate),
			Finished:     formatDate(g.Finished),
		}}, nil
	})

	createOp := huma.Operation{
		OperationID: "create-game",
		Method:      http.MethodPost,
		Path:        "/api/games",
		Summary:     "Create Game",
	}
	addAuth(&createOp, api, queries)
	huma.Register(api, createOp, func(ctx context.Context, input *struct{ Body model.GameInput }) (*struct{ Body model.Game }, error) {
		platformID, err := uuid.Parse(input.Body.PlatformID)
		if err != nil {
			return nil, huma.Error400BadRequest("invalid platform_id")
		}
		ry, err := parseDate(input.Body.ReleaseDate)
		if err != nil || !ry.Valid {
			return nil, huma.Error400BadRequest("invalid or missing release_date (expected YYYY-MM-DD)")
		}
		fin, err := parseDate(input.Body.Finished)
		if err != nil {
			return nil, huma.Error400BadRequest("invalid finished date (expected YYYY-MM-DD)")
		}

		game, err := queries.CreateGame(ctx, db.CreateGameParams{
			UserID:      userFromContext(ctx).ID,
			PlatformID:  platformID,
			Name:        input.Body.Name,
			Score:       input.Body.Score,
			ReleaseDate: ry,
			Finished:    fin,
		})
		if err != nil {
			return nil, dbError(err)
		}
		return &struct{ Body model.Game }{Body: model.Game{
			ID:           game.ID.String(),
			Name:         game.Name,
			PlatformID:   game.PlatformID.String(),
			PlatformName: game.PlatformName,
			Score:        game.Score,
			ReleaseDate:  formatDate(game.ReleaseDate),
			Finished:     formatDate(game.Finished),
		}}, nil
	})

	updateOp := huma.Operation{
		OperationID: "update-game",
		Method:      http.MethodPut,
		Path:        "/api/games/{id}",
		Summary:     "Update Game",
	}
	addAuth(&updateOp, api, queries)
	huma.Register(api, updateOp, func(ctx context.Context, input *struct {
		ID   uuid.UUID `path:"id"`
		Body model.GameInput
	}) (*struct{ Body model.Game }, error) {
		platformID, err := uuid.Parse(input.Body.PlatformID)
		if err != nil {
			return nil, huma.Error400BadRequest("invalid platform_id")
		}
		ry, err := parseDate(input.Body.ReleaseDate)
		if err != nil || !ry.Valid {
			return nil, huma.Error400BadRequest("invalid or missing release_date (expected YYYY-MM-DD)")
		}
		fin, err := parseDate(input.Body.Finished)
		if err != nil {
			return nil, huma.Error400BadRequest("invalid finished date (expected YYYY-MM-DD)")
		}

		game, err := queries.UpdateGame(ctx, db.UpdateGameParams{
			ID:          input.ID,
			UserID:      userFromContext(ctx).ID,
			PlatformID:  platformID,
			Name:        input.Body.Name,
			Score:       input.Body.Score,
			ReleaseDate: ry,
			Finished:    fin,
		})
		if err != nil {
			return nil, dbError(err)
		}
		return &struct{ Body model.Game }{Body: model.Game{
			ID:           game.ID.String(),
			Name:         game.Name,
			PlatformID:   game.PlatformID.String(),
			PlatformName: game.PlatformName,
			Score:        game.Score,
			ReleaseDate:  formatDate(game.ReleaseDate),
			Finished:     formatDate(game.Finished),
		}}, nil
	})

	deleteOp := huma.Operation{
		OperationID: "delete-game",
		Method:      http.MethodDelete,
		Path:        "/api/games/{id}",
		Summary:     "Delete Game",
	}
	addAuth(&deleteOp, api, queries)
	huma.Register(api, deleteOp, func(ctx context.Context, input *struct {
		ID uuid.UUID `path:"id"`
	}) (*struct{}, error) {
		rows, err := queries.DeleteGame(ctx, db.DeleteGameParams{ID: input.ID, UserID: userFromContext(ctx).ID})
		if err != nil {
			return nil, dbError(err)
		}
		return nil, notFoundIfZero(rows)
	})
}