// Copyright 2026 The Gitea Authors. All rights reserved.
// SPDX-License-Identifier: MIT

package services

import (
	"context"
	"errors"
	"fmt"
	"net/http"
	"net/url"
	"sync"

	gitea "gitea.dev/sdk"
	"gitea.dev/tea/internal/transport"
)

// Organization is the public command representation of a Gitea organization.
type Organization struct {
	ID                        int64  `json:"id"`
	Name                      string `json:"name"`
	FullName                  string `json:"full_name"`
	Description               string `json:"description"`
	Website                   string `json:"website"`
	Location                  string `json:"location"`
	Visibility                string `json:"visibility"`
	RepoAdminChangeTeamAccess bool   `json:"repo_admin_change_team_access"`
}

// organization returns the ID of owner when it is an organization; a missing organization
// means a user owns the namespace.
func organization(ctx context.Context, client *transport.Client, owner string) (id int64, isOrg bool, err error) {
	org, _, err := call(ctx, client, func(ctx context.Context, c *gitea.Client) (*gitea.Organization, *gitea.Response, error) {
		return c.Organizations.GetOrg(ctx, owner)
	})
	if statusNotFound(err) {
		return 0, false, nil
	}
	if err != nil {
		return 0, false, err
	}
	if org.ID < 1 {
		return 0, false, fmt.Errorf("cannot verify the identity of organization %s", owner)
	}
	return org.ID, true, nil
}

// statusNotFound reports whether err is a 404 response.
func statusNotFound(err error) bool {
	failure, ok := errors.AsType[*transport.APIError](err)
	return ok && failure.Status == http.StatusNotFound
}

// OrganizationOptions permits explicit empty and false preference updates.
type OrganizationOptions struct {
	Name                      *string `json:"username,omitempty"`
	FullName                  *string `json:"full_name,omitempty"`
	Description               *string `json:"description,omitempty"`
	Website                   *string `json:"website,omitempty"`
	Location                  *string `json:"location,omitempty"`
	Visibility                *string `json:"visibility,omitempty"`
	RepoAdminChangeTeamAccess *bool   `json:"repo_admin_change_team_access,omitempty"`
}

// Organizations implements instance-scoped organization workflows.
type Organizations struct{ Client *transport.Client }

// List selects public organizations, your organizations, or a named user's organizations.
func (s Organizations) List(ctx context.Context, mine bool, username string, limit, page int) (Page[Organization], error) {
	orgs, err := listPage(limit, page, func(limit, page int) ([]*gitea.Organization, http.Header, error) {
		orgs, resp, err := call(ctx, s.Client, func(ctx context.Context, c *gitea.Client) ([]*gitea.Organization, *gitea.Response, error) {
			opts := gitea.ListOrgsOptions{ListOptions: listOptions(limit, page)}
			switch {
			case mine:
				return c.Organizations.ListMyOrgs(ctx, opts)
			case username != "":
				return c.Organizations.ListUserOrgs(ctx, username, opts)
			}
			return c.Organizations.ListOrgs(ctx, opts)
		})
		return orgs, headerOf(resp), err
	})
	return convertPage(orgs, organizationFrom), err
}

// convertPage maps a page of SDK items onto tea results.
func convertPage[S, T any](page Page[*S], convert func(*S) T) Page[T] {
	return Page[T]{Items: convertAll(page.Items, convert), More: page.More, Total: page.Total, Counted: page.Counted}
}

// View retrieves a named organization.
func (s Organizations) View(ctx context.Context, name string) (Organization, error) {
	org, _, err := call(ctx, s.Client, func(ctx context.Context, c *gitea.Client) (*gitea.Organization, *gitea.Response, error) {
		return c.Organizations.GetOrg(ctx, name)
	})
	if err != nil {
		return Organization{}, err
	}
	return organizationFrom(org), nil
}

// OrganizationSize counts what an organization holds; a count the account cannot read is nil.
type OrganizationSize struct {
	Members, Teams, Repositories *int
}

// Size counts the members, teams and repositories of an organization.
func (s Organizations) Size(ctx context.Context, name string) (OrganizationSize, error) {
	first := listOptions(1, 1)
	counts := []func(context.Context, *gitea.Client) (*gitea.Response, error){
		func(ctx context.Context, c *gitea.Client) (*gitea.Response, error) {
			_, resp, err := c.Organizations.ListOrgMembership(ctx, name, gitea.ListOrgMembershipOption{ListOptions: first})
			return resp, err
		},
		func(ctx context.Context, c *gitea.Client) (*gitea.Response, error) {
			_, resp, err := c.Organizations.ListOrgTeams(ctx, name, gitea.ListTeamsOptions{ListOptions: first})
			return resp, err
		},
		func(ctx context.Context, c *gitea.Client) (*gitea.Response, error) {
			_, resp, err := c.Repositories.ListOrgRepos(ctx, name, gitea.ListOrgReposOptions{ListOptions: first})
			return resp, err
		},
	}
	totals := make([]*int, len(counts))
	for i, count := range counts {
		total, err := listTotal(ctx, s.Client, count)
		if ctx.Err() != nil {
			return OrganizationSize{}, ctx.Err()
		}
		if err == nil {
			totals[i] = total
		}
	}
	return OrganizationSize{Members: totals[0], Teams: totals[1], Repositories: totals[2]}, nil
}

// listTotal returns the collection size a list request reports, or nil when the server does not count it.
func listTotal(ctx context.Context, client *transport.Client, list func(context.Context, *gitea.Client) (*gitea.Response, error)) (*int, error) {
	_, resp, err := call(ctx, client, func(ctx context.Context, c *gitea.Client) (struct{}, *gitea.Response, error) {
		resp, err := list(ctx, c)
		return struct{}{}, resp, err
	})
	if err != nil {
		return nil, err
	}
	if _, total, counted := pageHints(headerOf(resp)); counted {
		return &total, nil
	}
	return nil, nil
}

// Create creates an organization owned by the selected account.
func (s Organizations) Create(ctx context.Context, opts OrganizationOptions) (Organization, error) {
	org, _, err := call(ctx, s.Client, func(ctx context.Context, c *gitea.Client) (*gitea.Organization, *gitea.Response, error) {
		return c.Organizations.CreateOrg(ctx, gitea.CreateOrgOption{
			Name: deref(opts.Name), FullName: deref(opts.FullName), Description: deref(opts.Description),
			Website: deref(opts.Website), Location: deref(opts.Location), Visibility: gitea.VisibleType(deref(opts.Visibility)),
			RepoAdminChangeTeamAccess: deref(opts.RepoAdminChangeTeamAccess),
		})
	})
	if err != nil {
		return Organization{}, err
	}
	return organizationFrom(org), nil
}

// Edit changes only supplied organization preferences.
func (s Organizations) Edit(ctx context.Context, name string, opts OrganizationOptions) (Organization, error) {
	var org gitea.Organization
	// TODO(sdk): EditOrgOption needs pointer fields so omitted preferences stay unchanged, and EditOrg should return the organization.
	if err := sendJSON(ctx, s.Client, http.MethodPatch, "orgs/"+url.PathEscape(name), opts, &org); err != nil {
		return Organization{}, err
	}
	return organizationFrom(&org), nil
}

// Delete deletes the named organization.
func (s Organizations) Delete(ctx context.Context, name string) error {
	return do(ctx, s.Client, func(ctx context.Context, c *gitea.Client) (*gitea.Response, error) {
		return c.Organizations.DeleteOrg(ctx, name)
	})
}

// OrganizationMember identifies a member without exposing private profile fields.
type OrganizationMember struct {
	ID       int64  `json:"id"`
	Username string `json:"username"`
	FullName string `json:"full_name"`
	// Visibility of an organization membership is public or concealed; team members have none.
	Visibility string `json:"visibility,omitempty"`
}

// Membership visibilities.
const (
	MembershipPublic    = "public"
	MembershipConcealed = "concealed"
)

// MemberListOptions selects a page of organization members.
type MemberListOptions struct {
	// Public lists only public memberships, and Visibility reports the visibility of each one.
	// Gitea lists concealed members as public to administrators, so both check each membership on
	// its own, and Public drops the server's total, which counts concealed members too.
	Public, Visibility bool
	Limit, Page        int
}

// Members lists the members of an organization.
func (s Organizations) Members(ctx context.Context, name string, opts MemberListOptions) (Page[OrganizationMember], error) {
	users, err := listPage(opts.Limit, opts.Page, func(limit, page int) ([]*gitea.User, http.Header, error) {
		users, resp, err := call(ctx, s.Client, func(ctx context.Context, c *gitea.Client) ([]*gitea.User, *gitea.Response, error) {
			list := gitea.ListOrgMembershipOption{ListOptions: listOptions(limit, page)}
			if opts.Public {
				return c.Organizations.ListPublicOrgMembership(ctx, name, list)
			}
			return c.Organizations.ListOrgMembership(ctx, name, list)
		})
		return users, headerOf(resp), err
	})
	members := convertPage(users, memberFrom)
	if err != nil || !(opts.Public || opts.Visibility) {
		return members, err
	}
	public := make([]bool, len(members.Items))
	err = concurrently(len(members.Items), func(i int) (err error) {
		public[i], err = s.IsPublicMember(ctx, name, members.Items[i].Username)
		return err
	})
	if err != nil {
		return Page[OrganizationMember]{}, err
	}
	shown := members.Items[:0]
	for i, member := range members.Items {
		member.Visibility = MembershipConcealed
		if public[i] {
			member.Visibility = MembershipPublic
		}
		if !opts.Public || public[i] {
			shown = append(shown, member)
		}
	}
	members.Items = shown
	members.Counted = members.Counted && !opts.Public
	return members, nil
}

// concurrentRequests bounds the requests that concurrently keeps in flight.
const concurrentRequests = 8

// concurrently runs request for each index 0..n-1 with a few requests in flight, and returns their
// errors joined.
func concurrently(n int, request func(i int) error) error {
	errs := make([]error, n)
	slots := make(chan struct{}, concurrentRequests)
	var wg sync.WaitGroup
	for i := range n {
		slots <- struct{}{}
		wg.Go(func() {
			defer func() { <-slots }()
			errs[i] = request(i)
		})
	}
	wg.Wait()
	return errors.Join(errs...)
}

// IsMember reports whether username belongs to the organization.
func (s Organizations) IsMember(ctx context.Context, name, username string) (bool, error) {
	return s.check(ctx, func(ctx context.Context, c *gitea.Client) (*gitea.Response, error) {
		_, resp, err := c.Organizations.CheckOrgMembership(ctx, name, username)
		return resp, err
	})
}

// IsPublicMember reports whether username's membership of the organization is public.
func (s Organizations) IsPublicMember(ctx context.Context, name, username string) (bool, error) {
	return s.check(ctx, func(ctx context.Context, c *gitea.Client) (*gitea.Response, error) {
		_, resp, err := c.Organizations.CheckPublicOrgMembership(ctx, name, username)
		return resp, err
	})
}

// check runs a membership check that answers no with a 404.
func (s Organizations) check(ctx context.Context, op func(context.Context, *gitea.Client) (*gitea.Response, error)) (bool, error) {
	err := do(ctx, s.Client, op)
	if statusNotFound(err) {
		return false, nil
	}
	return err == nil, err
}

// RemoveMember removes an organization member and their organization access.
func (s Organizations) RemoveMember(ctx context.Context, name, username string) error {
	return do(ctx, s.Client, func(ctx context.Context, c *gitea.Client) (*gitea.Response, error) {
		return c.Organizations.DeleteOrgMembership(ctx, name, username)
	})
}

// SetMemberPublic changes public visibility of an existing membership.
func (s Organizations) SetMemberPublic(ctx context.Context, name, username string, public bool) error {
	return do(ctx, s.Client, func(ctx context.Context, c *gitea.Client) (*gitea.Response, error) {
		return c.Organizations.SetPublicOrgMembership(ctx, name, username, public)
	})
}