import axios from 'axios'
import { ref } from 'vue'

const api = axios.create({
  baseURL: '/api',
  timeout: 30000
})

export function useApi() {
  const loading = ref(false)
  const error = ref(null)

  const handleError = (e, fallback = null) => {
    const status = e?.response?.status
    const message = e?.response?.data?.error || e?.message || 'Request failed'
    error.value = { status, message }
    console.error(`API error [${status}]:`, message)
    if (fallback !== null) return fallback
    throw e
  }

  // ============== Projects ==============
  const fetchProjects = async () => {
    loading.value = true
    error.value = null
    try {
      const response = await api.get('/projects')
      return response.data
    } catch (e) {
      handleError(e, [])
      return []
    } finally {
      loading.value = false
    }
  }

  const fetchProject = async (id) => {
    loading.value = true
    error.value = null
    try {
      const response = await api.get(`/projects/${id}`)
      return response.data
    } catch (e) {
      handleError(e, null)
      return null
    } finally {
      loading.value = false
    }
  }

  const createProject = async (data) => {
    loading.value = true
    error.value = null
    try {
      const response = await api.post('/projects', data)
      return response.data
    } catch (e) {
      handleError(e, null)
      return null
    } finally {
      loading.value = false
    }
  }

  const updateProject = async (id, data) => {
    loading.value = true
    error.value = null
    try {
      let response
      if (data instanceof FormData) {
        response = await api.put(`/projects/${id}`, data, {
          headers: { 'Content-Type': 'multipart/form-data' }
        })
      } else {
        // Wrap in FormData for multipart backend endpoint
        const formData = new FormData()
        if (data.name != null) formData.append('name', data.name)
        if (data.description != null) formData.append('description', data.description)
        response = await api.put(`/projects/${id}`, formData, {
          headers: { 'Content-Type': 'multipart/form-data' }
        })
      }
      return response.data
    } catch (e) {
      handleError(e, null)
      return null
    } finally {
      loading.value = false
    }
  }

  const deleteProject = async (id) => {
    loading.value = true
    error.value = null
    try {
      await api.delete(`/projects/${id}`)
      return true
    } catch (e) {
      handleError(e, false)
      return false
    } finally {
      loading.value = false
    }
  }

  // ============== Reports ==============
  const fetchReports = async (projectId) => {
    loading.value = true
    error.value = null
    try {
      const response = await api.get(`/reports`, {
        params: projectId ? { projectId } : {}
      })
      return response.data
    } catch (e) {
      handleError(e, [])
      return []
    } finally {
      loading.value = false
    }
  }

  const fetchReportContent = async (reportId) => {
    loading.value = true
    error.value = null
    try {
      const response = await api.get(`/reports/${reportId}`)
      return { content: response.data.fileContent, type: response.data.fileType }
    } catch (e) {
      handleError(e, null)
      return null
    } finally {
      loading.value = false
    }
  }

  const fetchReportBytes = async (reportId) => {
    try {
      const response = await api.get(`/reports/${reportId}/download`, { responseType: 'arraybuffer' })
      return response.data
    } catch (e) {
      handleError(e, null)
      return null
    }
  }

  const fetchReportPdf = async (reportId) => {
    try {
      const response = await api.get(`/reports/${reportId}/pdf`, { responseType: 'arraybuffer' })
      return new Blob([response.data], { type: 'application/pdf' })
    } catch (e) {
      handleError(e, null)
      return null
    }
  }

  const uploadReport = async (file, projectId, fileType) => {
    loading.value = true
    error.value = null
    try {
      const formData = new FormData()
      formData.append('file', file)
      formData.append('projectId', projectId)
      formData.append('fileType', fileType)
      const response = await api.post('/reports', formData, {
        headers: { 'Content-Type': 'multipart/form-data' }
      })
      return response.data
    } catch (e) {
      handleError(e, null)
      return null
    } finally {
      loading.value = false
    }
  }

  const deleteReport = async (id) => {
    loading.value = true
    error.value = null
    try {
      await api.delete(`/reports/${id}`)
      return true
    } catch (e) {
      handleError(e, false)
      return false
    } finally {
      loading.value = false
    }
  }

  return {
    loading,
    error,
    // projects
    fetchProjects,
    fetchProject,
    createProject,
    updateProject,
    deleteProject,
    // reports
    fetchReports,
    fetchReportContent,
    fetchReportBytes,
    fetchReportPdf,
    uploadReport,
    deleteReport
  }
}