package api

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

	"git.golem15.com/golem15/sm-seo-plugin/classes"
	"git.golem15.com/golem15/sm-seo-plugin/classes/crawl"
	"git.golem15.com/golem15/sm-seo-plugin/models"
	"gorm.io/gorm"
)

// StartCrawlInput is the body of POST /_seo/api/v1/crawls: nothing.
type StartCrawlInput struct{}

// CrawlView is a crawl in an answer.
type CrawlView struct {
	ID          uint       `json:"id"`
	Status      string     `json:"status"`
	Trigger     string     `json:"trigger"`
	TriggerName string     `json:"trigger_name,omitempty"`
	Site        string     `json:"site"`
	MaxPages    int        `json:"max_pages"`
	Pages       int        `json:"pages"`
	LimitHit    bool       `json:"limit_hit"`
	Error       string     `json:"error,omitempty"`
	StartedAt   *time.Time `json:"started_at"`
	FinishedAt  *time.Time `json:"finished_at"`
	CreatedAt   *time.Time `json:"created_at"`
}

// crawlView is the answer form of a crawl.
func crawlView(c models.Crawl) CrawlView {
	return CrawlView{
		ID: c.ID, Status: c.Status, Trigger: c.Trigger, TriggerName: c.TriggerName, Site: c.Site,
		MaxPages: c.MaxPages, Pages: c.Pages, LimitHit: c.LimitHit, Error: c.Error,
		StartedAt: c.StartedAt, FinishedAt: c.FinishedAt, CreatedAt: c.CreatedAt,
	}
}

// StartCrawl serves POST /_seo/api/v1/crawls (D-14, P33-39): it queues a
// crawl started by the administrator (trigger admin, or mcp through MCP)
// and answers 202 with it. A crawl already queued or running refuses with
// 409 crawls.already_running, a missing site address with 422
// crawls.no_site_url.
func StartCrawl(service func() *classes.Service) http.HandlerFunc {
	return manage(service, func(ctx context.Context, svc *classes.Service, r *http.Request) (int, any, error) {
		var row models.Crawl
		err := write(ctx, svc, func(ctx context.Context, tx *gorm.DB) error {
			_, name, viaMCP := svc.Actor(ctx, tx)
			trigger := models.TriggerAdmin
			if viaMCP {
				trigger = models.TriggerMCP
			}
			var err error
			row, err = crawl.Start(ctx, svc, tx, trigger, name)
			return err
		})
		if err != nil {
			return 0, nil, StartRefusal(ctx, svc, err)
		}
		return http.StatusAccepted, map[string]any{"data": crawlView(row), "message": svc.PhraseCtx(ctx, "golem15.seo::lang.crawls.started", nil)}, nil
	})
}

// StartRefusal maps a refused start to its answer.
func StartRefusal(ctx context.Context, svc *classes.Service, err error) error {
	var running *crawl.AlreadyRunningError
	switch {
	case errors.As(err, &running):
		return &apiError{Status: http.StatusConflict, Body: map[string]any{
			"error":    "crawls.already_running",
			"crawl_id": running.Crawl.ID,
			"message":  RunningMessage(ctx, svc, running),
		}}
	case errors.Is(err, crawl.ErrNoSiteURL):
		return &apiError{Status: http.StatusUnprocessableEntity, Body: map[string]any{
			"error":   "crawls.no_site_url",
			"message": svc.PhraseCtx(ctx, "golem15.seo::lang.crawls.no_site_url", nil),
		}}
	}
	return err
}

// RunningMessage is crawls.already_running with the running crawl's start.
func RunningMessage(ctx context.Context, svc *classes.Service, running *crawl.AlreadyRunningError) string {
	return svc.PhraseCtx(ctx, "golem15.seo::lang.crawls.already_running", map[string]string{"time": running.Since().UTC().Format("2006-01-02 15:04 UTC")})
}