export const useVariableSubstitution = () => {
  const { environments, selectedEnvironment } = useApiPlatform()

  // Get the currently selected environment
  const currentEnvironment = computed(() => {
    if (!selectedEnvironment.value) return null
    return environments.value.find(env => env.id === selectedEnvironment.value)
  })

  // Create a variables map for quick lookup
  const variablesMap = computed(() => {
    if (!currentEnvironment.value) return {}
    
    const map = {}
    currentEnvironment.value.variables.forEach(variable => {
      if (variable.key && variable.value) {
        map[variable.key] = variable.value
      }
    })
    return map
  })

  // Replace variables in a string ({{variableName}})
  const substituteVariables = (text) => {
    if (!text || typeof text !== 'string') return text
    if (!currentEnvironment.value) return text

    return text.replace(/\{\{([^}]+)\}\}/g, (match, variableName) => {
      const trimmedName = variableName.trim()
      return variablesMap.value[trimmedName] || match
    })
  }

  // Process an entire request object and substitute all variables
  const processRequest = (requestData) => {
    if (!currentEnvironment.value) return requestData

    const processed = JSON.parse(JSON.stringify(requestData))

    // Substitute URL
    processed.url = substituteVariables(processed.url)

    // Substitute headers
    if (processed.headers && Array.isArray(processed.headers)) {
      processed.headers.forEach(header => {
        header.key = substituteVariables(header.key)
        header.value = substituteVariables(header.value)
      })
    }

    // Substitute params
    if (processed.params && Array.isArray(processed.params)) {
      processed.params.forEach(param => {
        param.key = substituteVariables(param.key)
        param.value = substituteVariables(param.value)
      })
    }

    // Substitute auth values
    if (processed.auth) {
      if (processed.auth.bearer) {
        processed.auth.bearer = substituteVariables(processed.auth.bearer)
      }
      if (processed.auth.basic) {
        processed.auth.basic.username = substituteVariables(processed.auth.basic.username)
        processed.auth.basic.password = substituteVariables(processed.auth.basic.password)
      }
      if (processed.auth.apiKey) {
        processed.auth.apiKey.key = substituteVariables(processed.auth.apiKey.key)
        processed.auth.apiKey.value = substituteVariables(processed.auth.apiKey.value)
      }
      if (processed.auth.oauth2) {
        processed.auth.oauth2.authUrl = substituteVariables(processed.auth.oauth2.authUrl)
        processed.auth.oauth2.accessTokenUrl = substituteVariables(processed.auth.oauth2.accessTokenUrl)
        processed.auth.oauth2.clientId = substituteVariables(processed.auth.oauth2.clientId)
        processed.auth.oauth2.clientSecret = substituteVariables(processed.auth.oauth2.clientSecret)
        processed.auth.oauth2.redirectUri = substituteVariables(processed.auth.oauth2.redirectUri)
      }
    }

    // Substitute body content
    if (processed.requestBody) {
      if (processed.requestBody.raw) {
        processed.requestBody.raw = substituteVariables(processed.requestBody.raw)
      }
      if (processed.requestBody.formData && Array.isArray(processed.requestBody.formData)) {
        processed.requestBody.formData.forEach(item => {
          item.key = substituteVariables(item.key)
          item.value = substituteVariables(item.value)
        })
      }
      if (processed.requestBody.urlEncoded && Array.isArray(processed.requestBody.urlEncoded)) {
        processed.requestBody.urlEncoded.forEach(item => {
          item.key = substituteVariables(item.key)
          item.value = substituteVariables(item.value)
        })
      }
    }

    return processed
  }

  // Find all variables used in a text string
  const findVariables = (text) => {
    if (!text || typeof text !== 'string') return []
    
    const matches = text.match(/\{\{([^}]+)\}\}/g)
    if (!matches) return []
    
    return matches.map(match => {
      const variableName = match.replace(/[{}]/g, '').trim()
      return {
        name: variableName,
        found: !!variablesMap.value[variableName],
        value: variablesMap.value[variableName] || null
      }
    })
  }

  // Get all variables used in the current request
  const getRequestVariables = (requestData) => {
    const variables = new Set()
    
    // Check URL
    findVariables(requestData.url).forEach(v => variables.add(JSON.stringify(v)))
    
    // Check headers
    if (requestData.headers) {
      requestData.headers.forEach(header => {
        findVariables(header.key).forEach(v => variables.add(JSON.stringify(v)))
        findVariables(header.value).forEach(v => variables.add(JSON.stringify(v)))
      })
    }
    
    // Check params
    if (requestData.params) {
      requestData.params.forEach(param => {
        findVariables(param.key).forEach(v => variables.add(JSON.stringify(v)))
        findVariables(param.value).forEach(v => variables.add(JSON.stringify(v)))
      })
    }
    
    // Check body
    if (requestData.body?.raw) {
      findVariables(requestData.body.raw).forEach(v => variables.add(JSON.stringify(v)))
    }
    
    return Array.from(variables).map(v => JSON.parse(v))
  }

  return {
    currentEnvironment,
    variablesMap,
    substituteVariables,
    processRequest,
    findVariables,
    getRequestVariables
  }
}