package api

import (
	"context"
	"net/http"
	"strings"

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

// ListRulesInput is the query of GET /_seo/api/v1/rules.
type ListRulesInput struct {
	Page    int    `json:"page,omitempty" query:"page" jsonschema:"the page number, from 1"`
	PerPage int    `json:"per_page,omitempty" query:"per_page" jsonschema:"rows per page, at most 200 (50 by default)"`
	Search  string `json:"search,omitempty" query:"search" jsonschema:"text the address, title or description contains"`
	Match   string `json:"match,omitempty" query:"match" jsonschema:"exact or pattern"`
}

// RuleIDInput names one URL rule.
type RuleIDInput struct {
	ID uint `json:"id" path:"id" jsonschema:"the URL rule id"`
}

// CreateRuleInput is the body of POST /_seo/api/v1/rules.
type CreateRuleInput struct {
	URL           string  `json:"url" jsonschema:"the address: a path with an optional query; with match pattern * matches any text"`
	Match         *string `json:"match,omitempty" jsonschema:"exact (the default) or pattern"`
	Title         *string `json:"title,omitempty" jsonschema:"the SEO title"`
	Description   *string `json:"description,omitempty" jsonschema:"the meta description"`
	Canonical     *string `json:"canonical,omitempty" jsonschema:"the canonical URL"`
	Robots        *string `json:"robots,omitempty" jsonschema:"robots directives, for example noindex,follow"`
	OGTitle       *string `json:"og_title,omitempty" jsonschema:"the social title"`
	OGDescription *string `json:"og_description,omitempty" jsonschema:"the social description"`
	OGImage       *string `json:"og_image,omitempty" jsonschema:"the social image"`
	Note          *string `json:"note,omitempty" jsonschema:"an internal note"`
}

// UpdateRuleInput is PUT /_seo/api/v1/rules/{id}: only the fields sent are
// changed.
type UpdateRuleInput struct {
	ID            uint    `json:"id" path:"id" jsonschema:"the URL rule id"`
	URL           *string `json:"url,omitempty" jsonschema:"the address"`
	Match         *string `json:"match,omitempty" jsonschema:"exact or pattern"`
	Title         *string `json:"title,omitempty" jsonschema:"the SEO title"`
	Description   *string `json:"description,omitempty" jsonschema:"the meta description"`
	Canonical     *string `json:"canonical,omitempty" jsonschema:"the canonical URL"`
	Robots        *string `json:"robots,omitempty" jsonschema:"robots directives"`
	OGTitle       *string `json:"og_title,omitempty" jsonschema:"the social title"`
	OGDescription *string `json:"og_description,omitempty" jsonschema:"the social description"`
	OGImage       *string `json:"og_image,omitempty" jsonschema:"the social image"`
	Note          *string `json:"note,omitempty" jsonschema:"an internal note"`
}

// ruleBody is the decoded body of a rule write.
type ruleBody struct {
	URL           *string `json:"url"`
	Match         *string `json:"match"`
	Title         *string `json:"title"`
	Description   *string `json:"description"`
	Canonical     *string `json:"canonical"`
	Robots        *string `json:"robots"`
	OGTitle       *string `json:"og_title"`
	OGDescription *string `json:"og_description"`
	OGImage       *string `json:"og_image"`
	Note          *string `json:"note"`
}

// apply writes the fields sent onto r.
func (b ruleBody) apply(r *models.Rule) {
	for column, v := range map[string]*string{
		"url": b.URL, "match": b.Match, "title": b.Title, "description": b.Description,
		"canonical": b.Canonical, "robots": b.Robots, "og_title": b.OGTitle,
		"og_description": b.OGDescription, "og_image": b.OGImage, "note": b.Note,
	} {
		if v != nil {
			classes.SetRuleValue(r, column, strings.TrimSpace(*v))
		}
	}
}

// RuleJSON is a rule in an answer.
func RuleJSON(r models.Rule) map[string]any {
	out := classes.RuleValues(r)
	out["id"] = r.ID
	out["created_at"] = r.CreatedAt
	out["updated_at"] = r.UpdatedAt
	return out
}

// ListRules serves GET /_seo/api/v1/rules: URL rules by address, filtered
// by search text and match.
func ListRules(service func() *classes.Service) http.HandlerFunc {
	return manage(service, func(ctx context.Context, svc *classes.Service, r *http.Request) (int, any, error) {
		db, err := read(ctx, svc)
		if err != nil {
			return 0, nil, err
		}
		in := listParams(r)
		q := db.Model(&models.Rule{}).Order("url ASC, id ASC")
		if in.Search != "" {
			p := like(in.Search)
			q = q.Where("lower(url) LIKE ? OR lower(title) LIKE ? OR lower(description) LIKE ?", p, p, p)
		}
		if m := r.URL.Query().Get("match"); m != "" {
			q = q.Where("match = ?", m)
		}
		var rows []models.Rule
		total, err := paginate(q, in, &rows)
		if err != nil {
			return 0, nil, err
		}
		out := make([]map[string]any, 0, len(rows))
		for _, row := range rows {
			out = append(out, RuleJSON(row))
		}
		return http.StatusOK, listBody(out, in, total), nil
	})
}

// ShowRule serves GET /_seo/api/v1/rules/{id}.
func ShowRule(service func() *classes.Service) http.HandlerFunc {
	return manage(service, func(ctx context.Context, svc *classes.Service, r *http.Request) (int, any, error) {
		id, err := pathID(r, "id")
		if err != nil {
			return 0, nil, err
		}
		db, err := read(ctx, svc)
		if err != nil {
			return 0, nil, err
		}
		rule, err := classes.LoadRule(db, id)
		if err != nil {
			return 0, nil, err
		}
		return http.StatusOK, map[string]any{"data": RuleJSON(rule)}, nil
	})
}

// CreateRule serves POST /_seo/api/v1/rules: 201 with the rule, 422 for
// an invalid or taken address or invalid values.
func CreateRule(service func() *classes.Service) http.HandlerFunc {
	return manage(service, func(ctx context.Context, svc *classes.Service, r *http.Request) (int, any, error) {
		var body ruleBody
		if err := decode(r, maxBody, &body); err != nil {
			return 0, nil, err
		}
		rule := models.Rule{Match: models.MatchExact}
		body.apply(&rule)
		err := write(ctx, svc, func(ctx context.Context, tx *gorm.DB) error {
			return svc.SaveRule(ctx, tx, &rule)
		})
		if err != nil {
			return 0, nil, err
		}
		return http.StatusCreated, map[string]any{"data": RuleJSON(rule)}, nil
	})
}

// UpdateRule serves PUT /_seo/api/v1/rules/{id}: the fields sent change.
func UpdateRule(service func() *classes.Service) http.HandlerFunc {
	return manage(service, func(ctx context.Context, svc *classes.Service, r *http.Request) (int, any, error) {
		id, err := pathID(r, "id")
		if err != nil {
			return 0, nil, err
		}
		var body ruleBody
		if err := decode(r, maxBody, &body); err != nil {
			return 0, nil, err
		}
		var rule models.Rule
		err = write(ctx, svc, func(ctx context.Context, tx *gorm.DB) error {
			var err error
			if rule, err = classes.LoadRule(tx, id); err != nil {
				return err
			}
			body.apply(&rule)
			return svc.SaveRule(ctx, tx, &rule)
		})
		if err != nil {
			return 0, nil, err
		}
		return http.StatusOK, map[string]any{"data": RuleJSON(rule)}, nil
	})
}

// DeleteRule serves DELETE /_seo/api/v1/rules/{id}.
func DeleteRule(service func() *classes.Service) http.HandlerFunc {
	return manage(service, func(ctx context.Context, svc *classes.Service, r *http.Request) (int, any, error) {
		id, err := pathID(r, "id")
		if err != nil {
			return 0, nil, err
		}
		err = write(ctx, svc, func(ctx context.Context, tx *gorm.DB) error {
			rule, err := classes.LoadRule(tx, id)
			if err != nil {
				return err
			}
			return svc.DeleteRule(ctx, tx, rule)
		})
		if err != nil {
			return 0, nil, err
		}
		return http.StatusOK, map[string]any{"deleted": id}, nil
	})
}